SignalR Programming in Microsoft ASP.NET Professional José M. Aguilar PUBLISHED BY Microsoft Press A Division of Microsoft Corporation One Microsoft Way Redmond, Washington 98052-6399 Copyright © 2014 by Krasis Consulting S.L. All rights reserved. No part of the contents of this book may be reproduced or transmitted in any form or by any means without the written permission of the publisher. Library of Congress Control Number: 2014930486 ISBN: 978-0-7356-8388-4 Printed and bound in the United States of America. First Printing Microsoft Press books are available through booksellers and distributors worldwide. If you need support related to this book, email Microsoft Press Book Support at [email protected]. Please tell us what you think of this book at http://www.microsoft.com/learning/booksurvey. Microsoft and the trademarks listed at http://www.microsoft.com/about/legal/en/us/IntellectualProperty /Trademarks/EN-US.aspx are trademarks of the Microsoft group of companies. 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Copyeditor: Richard Carey Indexer: Lucie Haskins Cover: Twist Creative • Seattle and Joel Panchot To my parents, for all the love and unconditional support you gave that kid who only liked computers. And to my three girls, Inma, Inmita, and María, for putting up with me daily and yet being able to give me so much love and happiness. —JOSÉ M. AGUILAR Contents at a Glance Introduction xiii CHAPTER 1 Internet, asynchrony, multiuser…wow! 1 CHAPTER 2 HTTP: You are the client, and you are the boss 5 CHAPTER 3 Introducing SignalR 17 CHAPTER 4 Persistent connections 27 CHAPTER 5 Hubs 57 CHAPTER 6 Persistent connections and hubs from other threads 103 CHAPTER 7 Real-time multiplatform applications 117 CHAPTER 8 Deploying and scaling SignalR 151 CHAPTER 9 Advanced topics 181 Index 233 Contents Introduction .................................................... xiii Chapter 1 Internet, asynchrony, multiuser…wow! 1 Chapter 2 HTTP: You are the client, and you are the boss 5 HTTP operations ..................................................5 Polling: The answer?. 7 Push: The server takes the initiative ..................................8 WebSockets .................................................9 Server-Sent Events (API Event Source) .........................11 Push today. 12 The world needs more than just push .........................15 Chapter 3 Introducing SignalR 17 What does SignalR offer? .........................................18 Two levels of abstraction ..........................................19 Supported platforms .............................................20 OWIN and Katana: The new kids on the block .......................21 Installing SignalR .................................................25 Chapter 4 Persistent connections 27 Implementation on the server side .................................28 Mapping and configuring persistent connections ...............28 Events of a persistent connection .............................30 What do you think of this book? We want to hear from you! Microsoft is interested in hearing your feedback so we can continually improve our books and learning resources for you. To participate in a brief online survey, please visit: microsoft.com/learning/booksurvey vii Sending messages to clients .................................32 Asynchronous event processing ..............................34 Connection groups .........................................35 The OWIN startup class ......................................37 Implementation on the client side ..................................38 Initiating the connection by using the JavaScript client ..........38 Support for older browsers ..................................41 Support for cross-domain connections ........................41 Sending messages ..........................................43 Receiving messages .........................................45 Sending additional information to the server. 46 Other events available at the client ...........................47 Transport negotiation ............................................48 Adjusting SignalR configuration parameters. 50 Complete example: Tracking visitors ................................51 Project creation and setup ...................................52 Implementation on the client side ............................53 Implementation on the server side ............................54 Chapter 5 Hubs 57 Server implementation ...........................................58 Hub registration and configuration ...........................58 Creating hubs ..............................................59 Receiving messages .........................................60 Sending messages to clients .................................64 Sending messages to specific users ...........................68 State maintenance. .69 Accessing information about the request context ...............71 Notification of connections and disconnections ................72 Managing groups ...........................................72 Maintaining state at the server ...............................73 Client implementation ............................................78 viii Contents JavaScript clients. .79 Generating the proxy .......................................79 Manual generation of JavaScript proxies .......................81 Establishing the connection ..................................83 Sending messages to the server ..............................86 Sending additional information ...............................89 Receiving messages sent from the server ......................90 Logging ...................................................91 State maintenance. .92 Implementing the client without a proxy ......................93 Complete example: Shared drawing board ..........................96 Project creation and setup ...................................97 Implementation on the client side ............................98 Implementation on the server side ...........................100 Chapter 6 Persistent connections and hubs from other threads 103 Access from other threads. .103 External access using persistent connections ..................105 Complete example: Monitoring connections at the server ......106 Project creation and setup ..................................107 Implementing the website ..................................108 System for tracing requests (server side) ......................109 System for tracing requests (client side) .......................111 External access using hubs .......................................111 Complete example: Progress bar. 113 Project creation and setup ..................................113 Implementation on the client side ...........................114 Implementation on the server side ...........................115 Chapter 7 Real-time multiplatform applications 117 Multiplatform SignalR servers .....................................117 SignalR hosting in non-web applications. .118 SignalR hosting in platforms other than Windows .............126 Contents ix Multiplatform SignalR clients .....................................129 Accessing services from .NET non-web clients .................130 Consumption of services from other platforms ................149 Chapter 8 Deploying and scaling SignalR 151 Growing pains ..................................................152 Scalability in SignalR .............................................155 Scaling on backplanes ...........................................159 Windows Azure Service Bus .................................159 SQL Server ................................................165 Redis .....................................................167 Custom backplanes ..............................................170 Improving performance in SignalR services. 173 Server configuration .......................................174 Monitoring performance ...................................175 Chapter 9 Advanced topics 181 Authorization in SignalR .........................................181 Access control in persistent connections ......................181 Access control in hubs. .182 Client authentication .......................................184 An extensible framework .........................................191 Dependency injection ...........................................196 Manual dependency injection ...............................198 Releasing dependencies ....................................200 Inversion of Control containers ..............................200 Unit testing with SignalR .........................................205 Unit testing of hubs. .211 Unit testing persistent connections ..........................215